This paper documents and analyzes the pattern used in the Northwest Caucasian language Adyghe (Circassian) to express what the following five different constructions convey in other languages: headed and headless relative clauses, embedded declaratives, embedded polar interrogatives, and embedded constituent interrogatives. We argue that Adyghe encodes the meanings of all these embedded structures by means of the same syntactic construction, a relative clause. This pervasive use of relative clauses is possible due to mechanisms that are independently attested not just in Adyghe but also in more familiar languages like English. These mechanisms include concealed questions, polarity operators, and nomináis such as fact and question that can connect propositional attitude verbs or interrogative verbs with embedded clauses. We suggest that this extensive use of relative clauses in Adyghe is triggered by the absence of non-relative complementizer. We further show that this use is facilitated by their morphological visibility: a relativizer realized as a prefix on the verb, verbal affixation, a rich system of applicative heads hosting indirect arguments, and the availability of a case marker suffixed to headless relatives. We conclude by discussing the implications of the Adyghe system for the general design of embedding and subordination in natural language.